This invention relates to thermally-transferable ink compositions, and processes for transferring a dry layer of a thermally-transferable ink composition from a carrier to a receptor. The present invention is particularly useful in manufacturing sign faces by transferring indicia from a carrier to a receptor in a completely dry process.
Past techniques for manufacturing sign faces have not proven entirely satisfactory. For example, these techniques have involved masking or outlining the surface of the sign face so as to provide a desired outline, followed by painting (e.g., by brushing or spraying) to obtain the desired colored design. Such techniques are time consuming, messy, and require that steps be taken to provide adequate ventilation for the hazardous solvents employed with the paints or inks. Moreover, steps must be taken to insure that the solvents used in the inks do not destroy the surface to which they are applied. Furthermore, such prior art techniques frequently require that various inks be mixed. This, of course, means that a color match must be made before the mixed ink can be utilized.
Processes for thermally transferring indicia from a carrier (e.g., release liner) to a receptor (e.g., a fabric such as cotton) and composition useful therewith are also known. See for example U.S. Pat. Nos. 3,361,281; 3,519,463; 3,684,545; 3,928,710; and 4,037,008. These processes and compositions generally require the use of high heat and pressure to effect transfer. Typically temperatures of 120.degree. C. or more are required.
The use of the foregoing processes has not proven entirely satisfactory. For example, the temperatures employed require the use of large quantities of energy and limit the number of materials that can be utilized as receptors as the heat generated may degrade certain polymeric receptors. Still further, these prior art processes have not been found to provide strongly adhered images on uneven or textured and three dimensional substrates. Consequently, it is clear that a need exists for compositions, and processes for transferring thermally-transferable inks that overcome these disadvantages.